#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <string.h>
#include <stdbool.h>
#include <tgmath.h>

//https://www.nowcoder.com/practice/fe19f8a78a5148018f4be53ae9b5e11e?tpId=182&&tqId=34521&rp=1&ru=/ta/exam-all&qru=/ta/exam-all/question-ranking

double sumSeries(double input, int n) {
    double sum = input;
    for (int i = 1; i < n; i++) {
        input = sqrt(input);
        sum += input;
    }
    return sum;
}

int main() {
    double input = 0;
    int n = 0;
    while (scanf("%lf%d", &input, &n) != EOF) {
        printf("%.2f\n", sumSeries(input, n));
    }
    return 0;
}